NiFe_(2)O_(4) is a kind of bimetallic oxide possessing excellent theoretical capacity and application prospect in the field of supercapacitors.Whereas,due to the inherent poor conductivity of metal oxides,the performa...NiFe_(2)O_(4) is a kind of bimetallic oxide possessing excellent theoretical capacity and application prospect in the field of supercapacitors.Whereas,due to the inherent poor conductivity of metal oxides,the performance of NiFe_(2)O_(4) is not ideal in practice.Oxygen vacancies can not only enhance the conductivities of NiFe_(2)O_(4) but also provide better adsorption of OH,which is beneficial to the electrochemical performances.Hence,oxygen vacancies engineered NiFe_(2)O_(4)(NiFe_(2)O_(4)‒δ)is obtained through a two-step method,including a hydrothermal reaction and a further heat treatment in activated carbon bed.Results of electron paramagnetic resonance spectra indicate that more oxygen vacancies exist in the treated NiFe_(2)O_(4)‒δthan the original one.UV-Vis diffuse reflectance spectra prove that the treated NiFe_(2)O_(4)‒δowns better conductivity than the original NiFe_(2)O_(4).As for the electrochemical performances,the treated NiFe_(2)O_(4)‒δperforms a high specific capacitance of 808.02 F∙g^(‒1) at 1 A∙g^(‒1).Moreover,the asymmetric supercapacitor of NiFe_(2)O_(4)‒δ//active carbon displays a high energy density of 17.7 Wh∙kg^(‒1) at the power density of 375 W∙kg^(‒1).This work gives an effective way to improve the conductivity of metal oxides,which is beneficial to the application of metal oxides in supercapacitors.展开更多
基金supported by Major Basic Research Projects of Shandong Natural Science Foundation(Grant No.ZR2018ZB0104)Science and Technology Development Project of Shandong Province(Grant Nos.2016GGX102003 and 2017GGX20105)Natural Science Foundation of Shandong Province(Grant No.ZR2017BEM032).
文摘NiFe_(2)O_(4) is a kind of bimetallic oxide possessing excellent theoretical capacity and application prospect in the field of supercapacitors.Whereas,due to the inherent poor conductivity of metal oxides,the performance of NiFe_(2)O_(4) is not ideal in practice.Oxygen vacancies can not only enhance the conductivities of NiFe_(2)O_(4) but also provide better adsorption of OH,which is beneficial to the electrochemical performances.Hence,oxygen vacancies engineered NiFe_(2)O_(4)(NiFe_(2)O_(4)‒δ)is obtained through a two-step method,including a hydrothermal reaction and a further heat treatment in activated carbon bed.Results of electron paramagnetic resonance spectra indicate that more oxygen vacancies exist in the treated NiFe_(2)O_(4)‒δthan the original one.UV-Vis diffuse reflectance spectra prove that the treated NiFe_(2)O_(4)‒δowns better conductivity than the original NiFe_(2)O_(4).As for the electrochemical performances,the treated NiFe_(2)O_(4)‒δperforms a high specific capacitance of 808.02 F∙g^(‒1) at 1 A∙g^(‒1).Moreover,the asymmetric supercapacitor of NiFe_(2)O_(4)‒δ//active carbon displays a high energy density of 17.7 Wh∙kg^(‒1) at the power density of 375 W∙kg^(‒1).This work gives an effective way to improve the conductivity of metal oxides,which is beneficial to the application of metal oxides in supercapacitors.
